How Satellite Tagging Is Teaching Us About Sea Turtle Migration

Published December 13, 2013

The National Aquarium and Virginia Aquarium & Marine Science Center recently partnered to release four juvenile loggerhead sea turtles named Findlay, Rooney, Portsmouth, and Grenada at Sandbridge, Virginia on October 20, 2013. The animals were all treated for a range of injuries and illnesses and were in rehabilitation for varying amounts of time. While all four animals have unique rescue and rehabilitation stories, three of the four now have one significant factor in common - they are all taking part in a significant piece of research!

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The U.S. Navy is supporting the conduction of research that will provide valuable insights into sea turtle habitat use of the Chesapeake Bay and coastal Virginia waters. The project funds the deployment of acoustic transmitters and satellite tracking tags on rehabilitated and released sea turtles with the goal of learning more about residency times, migration intervals, and foraging areas within the Bay and its surrounding waters.

Acoustic transmitter tags work by emitting a sound signal or ‘ping’ that can be detected by networks of underwater receivers, commonly referred to as arrays. These acoustic monitoring arrays are installed in many coastal areas, including the Chesapeake Bay and have been valuable for understanding migration patterns and habitat use for many fish species, including endangered species of sturgeon!

Each tag transmits a specific coded signal that is used to identify the individual as it moves from one location to another. As the turtle moves around areas where receiving arrays are present, the arrays detect the pings from the tag and record the information, which is later downloaded by researchers for analysis.

Findlay, Rooney, and Portsmouth were also equipped with data logging satellite telemetry tags produced by Wildlife Computers and the Sea Mammal Research Unit. These tags can record the behaviors such as dive depth and duration and transmit that data back to researchers via satellites. In addition to the recorded data, each transmission also includes the GPS coordinates of the individual so that their movements can be tracked over long ranges.

As seen here, both tags were secured onto Portsmouth's carapace before his release!

The goal of this project is to leverage the Navy's existing underwater passive acoustic receiver array initially established to track sturgeon and the expertise of Virginia Aquarium researchers to tag sea turtles to gain insights into how sea turtles forage and migrate. From the underwater acoustic tags, we hope to learn about residency time and migration intervals by being able to tag more turtles at less cost. Analysis of data will be performed jointly between both the Navy and Virginia Aquarium.

Check out Rooney and Portsmouth’s rehabilitation pages on our website for more information and to track their progress!

Funding for the tagging work is provided by U.S. Fleet Forces Command and technical project management and collaboration on data analysis is being provided by Naval Facilities Engineering Command Atlantic.